The Justice Department's Office of the Inspector General found that former FBI Director James Comey deviated from FBI and DOJ norms while handling the bureau's investigation into Hillary Clinton's use of a private email server when she was secretary of state.

That finding is in a 568-page official report by the department's inspector general, Michael Horowitz, released Thursday afternoon.

Here are the report's main findings:

Comey departed "clearly and dramatically" from FBI and DOJ guidelines while overseeing the Clinton investigation.

Comey's decisions "negatively impacted the perception of the FBI" and the DOJ.

Comey usurped the authority of the attorney general when he announced during a July 2016 press conference that the FBI would not be recommending charges against Clinton, then the presumptive Democratic presidential nominee.

Comey often used a personal email account to conduct official FBI business.

The senior FBI officials Peter Strzok and Lisa Page may have had a "willingness to take official action" to hurt Donald Trump's chances of winning the 2016 election.

Strzok's and Page's text messages expressing pro-Clinton and anti-Trump views raised questions about whether they allowed their political leanings to interfere with their work.

While Comey's conduct was "insubordinate," his actions and those of others in the FBI were not affected by bias.

"We did not find documentary or testimonial evidence that improper considerations, including political bias, directly affected the specific investigative actions we reviewed," Horowitz wrote, adding: "The conduct by these employees cast a cloud over the entire FBI investigation."

Comey said in a tweet shortly after the report's release that he respected the OIG and that he had urged it to conduct its review.

"The conclusions are reasonable, even though I disagree with some," Comey added. "People of good faith can see an unprecedented situation differently. I pray no Director faces it again. Thanks to IG's people for hard work."

Strzok to Page: 'We'll stop' Trump from winning

Among the report's biggest revelations was a previously undisclosed text message from Strzok to Page that said "we'll stop" Trump from winning the election.

The two officials made headlines last year when it surfaced that they exchanged thousands of text messages expressing anti-Trump and pro-Clinton views during the Clinton inquiry and the investigation into Russia's interference in the 2016 US election.

They were initially working on the special counsel Robert Mueller's team but were subsequently moved within the bureau.

Thursday's report said Strzok's and Page's decisions to send politically charged messages to each other using FBI devices showed "extremely poor judgment and a gross lack of professionalism." Horowitz suggested they may also violate official FBI policy.

The report outlines several other instances in which FBI officials exchanged messages harshly criticizing Trump and his supporters.

"I can't stop crying," one FBI employee told an official described as "FBI Attorney 2" on November 9, 2016.

Later in the exchange, the employee described Trump supporters as "all poor to middle class, uneducated, lazy POS that think he will magically grant them jobs for doing nothing."

"They probably didn't watch the debates, aren't fully educated on his policies, and are stupidly wrapped up in his unmerited enthusiasm," the employee continued.

In another exchange, one FBI agent told another that they "would rather have brunch with trump and a bunch of his supporters like the ones from ohio that are retarded."

2 highly scrutinized moves before the 2016 election

Hillary Clinton. Associated Press/Andrew Harnik

Horowitz's investigation into Comey and the FBI was announced in January 2017.

At the center of the inquiry are two controversial decisions Comey made during the 2016 presidential campaign.

The first was to call the July 2016 press conference, where he said he had not consulted with the DOJ about the statement he was about to make.

Comey's move was considered highly unusual, given that making the announcement should have fallen to the attorney general at the time, Loretta Lynch.

In explaining his decision after Trump fired him last year, Comey accused Lynch of having a "tortured half-out, half-in" approach to the investigation.

Comey said he was also concerned by her decision not to recuse herself from the investigation following a controversial and much-publicized meeting on an airplane tarmac with former President Bill Clinton.

Those misgivings made up the basis of the FBI director's decision to independently announce that the bureau would not recommend charges against Clinton. Lynch criticized Comey after he made his comments and reiterated that she did not act improperly during the investigation.

Comey again drew scrutiny when, three months after the press conference, he sent a letter to Congress announcing that the FBI was reopening the Clinton investigation after it discovered new emails it believed could be relevant.

He sent the letter on October 28, 2016, just 11 days before Election Day. Clinton has repeatedly said since then that she believes Comey's letter was the final nail in the coffin for her presidential bid.

Comey has said he would have refrained from sending the letter if Lynch had told him not to, but he drew criticism for sending it at all.

Thursday's report castigated Comey for sending the letter and threw cold water on his argument that he was forced to make a choice between "two doors," one labeled "speak" and the other "conceal."

The report said the choice was "a false dichotomy."

It added: "The two doors were actually labeled 'follow policy/practice' and 'depart from policy/practice.' His task was not to conduct an ad hoc comparison of case-specific outcomes and risks. Rather, the burden was on him to justify an extraordinary departure from these established norms, policies, and precedent."

ABC News reported last week that at least one senior DOJ official told the FBI that publicizing such a detail about a sensitive investigation so close to the election would violate department policy and federal guidelines about disclosing information about ongoing investigations.

Comey said after his firing that it made him "nauseous" to think his actions had swayed the outcome of the election, but he has maintained that he did what he thought was right at the time.